U.S. patent application number 16/667946 was filed with the patent office on 2020-02-27 for heat storage device.
The applicant listed for this patent is Panasonic Corporation. Invention is credited to TAKASHI KUBO, HIRONOBU MACHIDA, TATSUYA NAKAMURA, KENTARO SHII, MOTOHIRO SUZUKI, SHINSUKE TAKEGUCHI, NAOYUKI TANI.
Application Number | 20200063012 16/667946 |
Document ID | / |
Family ID | 64741410 |
Filed Date | 2020-02-27 |
United States Patent
Application |
20200063012 |
Kind Code |
A1 |
KUBO; TAKASHI ; et
al. |
February 27, 2020 |
HEAT STORAGE DEVICE
Abstract
Provided is a heat storage device (10) of the present disclosure
comprises a heat storage material (12) containing sodium acetate
trihydrate; a first electrode having a surface which is in contact
with the heat storage material and formed of at least one selected
from the group consisting of silver, a silver alloy, and a silver
compound; a second electrode in contact with the heat storage
material; an inorganic porous material contained in the heat
storage material; and a power supply (14) for applying a voltage to
the first electrode and the second electrode. The inorganic porous
material has an average pore diameter of not more than 50
nanometers. The present invention provides a heat storage device
capable of releasing heat by releasing a supercooled state by
voltage application. The heat storage device can be used
repeatedly.
Inventors: |
KUBO; TAKASHI; (Hyogo,
JP) ; SUZUKI; MOTOHIRO; (Osaka, JP) ; MACHIDA;
HIRONOBU; (Nara, JP) ; TAKEGUCHI; SHINSUKE;
(Osaka, JP) ; SHII; KENTARO; (Osaka, JP) ;
TANI; NAOYUKI; (Osaka, JP) ; NAKAMURA; TATSUYA;
(Osaka, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Panasonic Corporation |
Osaka |
|
JP |
|
|
Family ID: |
64741410 |
Appl. No.: |
16/667946 |
Filed: |
October 30, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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PCT/JP2018/011975 |
Mar 26, 2018 |
|
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16667946 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F01P 3/20 20130101; F28D
20/028 20130101; C09K 5/063 20130101; F28D 20/023 20130101; C09K
5/06 20130101 |
International
Class: |
C09K 5/06 20060101
C09K005/06; F28D 20/02 20060101 F28D020/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 29, 2017 |
JP |
2017-126876 |
Claims
1. A method for releasing heat, the method comprising: (pa1)
crystallizing a heat storage material containing sodium acetate
trihydrate; (pa2) melting the heat storage material at a
temperature of not more than 80 degrees Celsius after the step
(pa1); (a) cooling the heat storage device comprising the heat
storage material to bring the sodium acetate trihydrate into a
supercooled state; wherein the heat storage device comprises: a
first electrode having a surface which is in contact with the heat
storage material, wherein the surface is formed of at least one
selected from the group consisting of silver, a silver alloy, and a
silver compound; a second electrode in contact with the heat
storage material; an inorganic porous material contained in the
heat storage material; and a power supply for applying a voltage to
the first electrode and the second electrode; and the inorganic
porous material has an average pore diameter of not less than 10
nanometers and not more than 50 nanometers; and the inorganic
porous material is formed of silica gel; (b) applying a voltage to
the first electrode and the second electrode with the power supply
at a temperature of not more than 58 degrees Celsius after the step
(a) to release the heat from the heat storage material; and (c)
heating the heat storage device at a temperature of not less than
58 degrees Celsius and not more than 80 degrees Celsius to melt the
sodium acetate trihydrate after the step (b).
2. The method according to claim 1, wherein the step (pa1)
comprises: (pa11) cooling the heat storage material to a
temperature of not more than minus 30 degrees Celsius.
3. The method according to claim 1, wherein the step (pa1)
comprises: (pa12) adding a crystal of sodium acetate trihydrate to
the heat storage material in the supercooled state.
4. A method for applying heat to an engine included in a vehicle,
the method comprising: (pa1) crystallizing a heat storage material
containing sodium acetate trihydrate; (pa2) melting the heat
storage material at a temperature of not more than 80 degrees
Celsius after the step (pa1); (a) cooling the heat storage device
comprising a heat storage material to bring the sodium acetate
trihydrate into a supercooled state; wherein the heat storage
device is included in the vehicle; the heat storage device
comprises: a first electrode having a surface which is in contact
with the heat storage material; the surface being formed of at
least one selected from the group consisting of silver, a silver
alloy, and a silver compound; a second electrode in contact with
the heat storage material; an inorganic porous material contained
in the heat storage material; and a power supply for applying a
voltage to the first electrode and the second electrode; and the
inorganic porous material has an average pore diameter of not less
than 10 nanometers and not more than 50 nanometers; and the
inorganic porous material is formed of silica gel; (b) applying a
voltage to the first electrode and the second electrode with the
power supply at a temperature of not more than 58 degrees Celsius
to apply the heat to the engine due to release of the heat from the
heat storage material; (c) heating the heat storage device at a
temperature of not less than 58 degrees Celsius and not more than
80 degrees Celsius to melt the sodium acetate trihydrate after the
step (b).
5. The method according to claim 4, wherein the step (pa1)
comprises: (pa11) cooling the heat storage material to a
temperature of not more than minus 30 degrees Celsius.
6. The method according to claim 4, wherein the step (pa1)
comprises: (pa12) adding a crystal of sodium acetate trihydrate to
the heat storage material in the supercooled state.
Description
BACKGROUND
1. Technical Field
[0001] The present invention relates to a heat storage device.
2. Description of the Related Art
[0002] Patent Literature 1 discloses a heat storage system using
sodium acetate trihydrate as a heat storage material.
[0003] Sodium acetate trihydrate melts at a melting point of 58
degrees Celsius. However, sodium acetate trihydrate does not
solidify immediately even when cooled to not more than the melting
point thereof. A state in which a liquid is not solidified even
when cooled to not more than the melting point is referred to as a
supercooled state.
[0004] After the heat storage material containing sodium acetate
trihydrate is heated and melted, the heat storage material is
cooled until the heat storage material is in the supercooled state.
In this way, latent heat is stored in the sodium acetate
trihydrate. When heat is required, the supercooled state of the
heat storage material containing the sodium acetate trihydrate is
released. The state of the sodium acetate trihydrate is changed
from a liquid state to a solid state. Due to the change, heat is
released from the sodium acetate trihydrate. In other words, the
latent heat is taken out. In this way, the heat storage effect is
achieved.
[0005] Patent Literature 2 discloses a heat storage tank comprising
a silver electrode for applying a voltage to a heat storage
material in a supercooled state as a means for releasing the
supercooled state.
[0006] Patent Literature 3 discloses a supercooling preventing
agent, a heat storage method, and a heat storage system. The
production method according to Patent Literature 3 comprises steps
of immersing a porous material in a melt containing sodium acetate
trihydrate, and cooling the melt and the porous material at not
more than a temperature at which the supercooling of the melt is
released while maintaining the porous material immersed in the
melt. Heat is stored by heating the heat storage material
containing the sodium acetate trihydrate at a temperature higher
than the melting point of sodium acetate trihydrate. In the
presence of the supercooling preventing agent produced according to
the method according to Patent Literature 3, heat is drawn from the
heat storage material in such a way that the sodium acetate
trihydrate changes from liquid phase to solid phase.
CITATION LIST
Patent Literature
[0007] Patent Literature 1: Japanese Patent Application Publication
No. 2008-20177 [0008] Patent Literature 2: Japanese Patent
Application Publication No. Sho 61-204293 [0009] Patent Literature
3: Japanese Patent Application Publication No. 2013-067720
SUMMARY
[0010] An object of the present invention is to provide a heat
storage device capable of releasing heat by releasing supercooling
by voltage application and capable of being used repeatedly.
[0011] The present invention is a heat storage device
comprising:
[0012] a heat storage material containing sodium acetate
trihydrate;
[0013] a first electrode having a surface which is in contact with
the heat storage material; the surface being formed of at least one
selected from the group consisting of silver, a silver alloy, and a
silver compound, a second electrode in contact with the heat
storage material;
[0014] an inorganic porous material contained in the heat storage
material; and
[0015] a power supply for applying a voltage to the first electrode
and the second electrode,
[0016] wherein
[0017] the inorganic porous material has an average pore diameter
of not more than 50 nanometers.
[0018] The present invention includes a heat releasing method using
the above-mentioned heat storage device.
[0019] The present invention includes a vehicle comprising the
above-mentioned heat storage device. Furthermore, the present
invention includes a method for applying heat to an engine in the
vehicle.
[0020] The present invention provides a heat storage device capable
of releasing heat by releasing supercooling by voltage application
and capable of being used repeatedly.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 shows a schematic view of a heat storage device
according to an embodiment.
[0022] FIG. 2 shows a schematic view of a pore structure of an
activated carbon.
DETAILED DESCRIPTION OF THE EMBODIMENT
[0023] Hereinafter, an embodiment of the present invention will be
described with reference to the drawings.
[0024] (Heat Storage Device 10)
[0025] FIG. 1 shows a schematic view of a heat storage device 10
according to the embodiment. In FIG. 1, the heat storage device 10
comprises a heat storage tank 11 filled with a heat storage
material 12, a pair of electrodes 13 comprising a first electrode
13a and a second electrode 13b, a direct-current power supply 14,
and a switch 15.
[0026] (Heat Storage Tank 11)
[0027] The heat storage tank 11 is maintained warm by a heat
insulating material. An example of the heat insulating material is
glass wool. The heat storage tank 11 contains the heat storage
material 12. In the present embodiment, the heat storage material
12 is sodium acetate trihydrate. In other words, the heat storage
material 12 contains sodium acetate trihydrate as a main
component.
[0028] (Heat Storage Material 12)
[0029] The heat storage material 12 contains an inorganic porous
material.
[0030] As will be described in detail later, the present inventors
believe that the inside of pores of the inorganic porous material
has a fine solid-phase heat storage material 12. In the present
specification, the fine solid-phase heat storage material 12 is
also referred to as a "cluster". The fine solid-phase heat storage
material 12 contained in the pores has stronger intermolecular
bonding than the heat storage material 12 located outside the pores
due to capillary condensation.
[0031] For this reason, when the heat storage material 12 is
heated, the heat storage material 12 contained in the pores melts
more slowly than the heat storage material 12 located outside the
pores. As a result, it is possible to enhance viability of the
cluster after the heat storage material 12 is held at a high
temperature in the liquid state. Therefore, even after the heat
storage material 12 is held at the high temperature in the liquid
state, voltage application can cancel the supercooled state of
sodium acetate trihydrate at a temperature of not more than 58
degrees Celsius. In more detail, even after the heat storage
material 12 is held at the high temperature in the liquid state,
since the cluster (i.e., the fine solid-phase heat storage material
12) is located in the pores, the voltage is applied to the heat
storage material 12 in the supercooled state to crystalize the heat
storage material 12 in such a way the crystalized heat storage
material 12 is spread from the center of the cluster to the
surroundings thereof. In other words, the crystallization of the
heat storage material 12 at the time when the voltage is applied to
the heat storage material 12 in the supercooled state starts from
the cluster.
[0032] The inorganic porous material contained in the heat storage
material 12 has an average pore diameter of not more than 50
nanometers. The pore diameter of the inorganic porous material can
be measured by a commonly used method. For example, the pore
diameter can be calculated based on a nitrogen gas adsorption
method or a mercury intrusion method. The term "average pore
diameter" used in the present specification means a pore diameter
at a peak value of a pore diameter distribution curve derived from
an adsorption isotherm of nitrogen by a Barret-Joyner-Halenda
method (hereinafter, referred to as "BJH method") or a
Horvath-Kawazoe method (hereinafter, referred to as "HK method").
The pore diameter distribution curve is drawn on a graph in which
the horizontal axis and the vertical axis thereof represent the
pore diameter and the volume of pores respectively. The average
pore diameter is equal to the pore diameter at the maximum of the
pore volume. Alternatively, the term "average pore diameter" used
in the present specification means the pore diameter at the peak
value of the pore diameter distribution curve provided by the
mercury intrusion method. In the present specification, the average
pore diameter of zeolite, mesoporous silica, or activated carbon is
calculated by the nitrogen gas adsorption method. The average pore
diameter of silica gel is calculated by the mercury intrusion
method. The average pore diameter of the commercially available
inorganic porous material is often disclosed in its catalog.
[0033] As demonstrated in the comparative example 2 which will be
described later, in case where the average pore diameter is more
than 50 nanometers, the supercooled state of the sodium acetate
trihydrate fails to be released, even when a voltage is applied
after the heat storage material 12 is held at a high temperature in
a liquid state. The present inventors believe that this is because,
in the case where the average pore diameter is more than 50
nanometers, the viability of the clusters after the heat storage
material 12 is held at the high temperature in the liquid state is
significantly lowered due to decrease in the effect of the
capillary condensation. Needless to say, even in the case where the
heat storage material 12 does not contain the inorganic porous
material, the supercooled state of sodium acetate trihydrate fails
to be released for the same reason as described above.
[0034] On the other hand, the lower limit of the average pore
diameter of the inorganic porous material is not limited, as long
as the inside of the pores has the heat storage material 12 and the
melting of the cluster is suppressed. As one example, the average
pore diameter of the inorganic porous material is not less than 0.9
nanometers.
[0035] The material of the inorganic porous material is, for
example, a metal oxide or carbon. An example of the metal oxide is
zeolite, silica, alumina, titania, or a tungsten oxide.
[0036] As demonstrated in the inventive examples which will be
described below, the desirable inorganic porous material is
activated carbon or silica gel.
[0037] Activated carbon and silica gel have, on their surfaces,
pores each having a size of not more than 50 nanometers
(hereinafter, referred to as "micro mesopores") and pores each
having a size of more than 50 nanometers (hereinafter, referred to
as "macropores"). The micro mesopores communicate with the
macropores.
[0038] FIG. 2 shows a schematic view of the pore structure of the
inorganic porous material. As shown in FIG. 2, a surface 20 of the
activated carbon has a macropore 21. The micro mesopores 22 are
disposed inside the activated carbon so as to communicate with the
macropore 21. Therefore, the heat storage material 12 is easily
introduced into the micro mesopores 22. In this way, the fine
solid-phase heat storage material 12 is formed in the micro
mesopores. This will be described in detail later.
[0039] As a result, the heat storage material 12 in larger amount
can be disposed in the micro mesopores 22 each having a size of not
more than 50 nanometers, as compared to an inorganic porous
material having no macropore 21 such as mesoporous silica. As a
result, the viability of the cluster is further improved after the
heat storage material 12 is held at the high temperature in the
liquid state. For this reason, even if the heat storage material 12
is held at the high temperature for a long time in the liquid
state, the supercooling can be released by voltage application.
[0040] The heat storage material 12 may contain an additive. An
example of the additives is a supercooling release aid, a viscosity
modifier, a foam stabilizer, an antioxidant, a defoamer, an
abrasive grain, a filler, a pigment, a dye, a colorant, a
thickener, a surfactant, a flame retardant, a plasticizers, a
lubricant, an antistatic agent, a heat stabilizer, a tackifier, a
curing catalyst, a stabilizer, a silane coupling agent, or a wax.
The type and amount of the additives are not limited, as long as
the object of the present invention is not hindered. The additives
do not have to be added to the heat storage material 12.
[0041] (Method for Forming Fine Solid-Phase Heat Storage Material
12 in Pores of Inorganic Porous Material)
[0042] The method for forming the fine solid-phase heat storage
material 12 in the pores of the inorganic porous material will be
described below. The heat storage material 12 containing the
inorganic porous material is heated at a temperature equal to or
higher than the melting point of the heat storage material 12
(i.e., 58 degrees Celsius). Thus, the heat storage material 12 is
in a liquid state. Next, the heat storage material 12 is allowed to
leave at rest for a predetermined time, while the temperature is
maintained. During this time, the heat storage material 12 is
introduced into the pores of the inorganic porous material. The
present inventors believe that the heat storage material 12 is
introduced into the pores of the inorganic porous material by
capillary action.
[0043] Thereafter, the heat storage material 12 is cooled at a
temperature of minus 30 degrees Celsius or lower. Alternatively,
the heat storage material 12 is supercooled by being cooled to not
more than 58 degrees Celsius, and then, a seed crystal formed of
sodium acetate trihydrate is added to the heat storage material 12.
The heat storage material 12 in the pores is crystallized by
cooling at a low temperature of not more than minus 30 degrees
Celsius or by the addition of the seed crystal in the supercooled
state. In other words, the heat storage material 12 in the pore
changes from the liquid phase to the solid phase. In this way, the
fine solid-phase heat storage material 12 can be formed in the
pores of the inorganic porous material.
[0044] (Electrode, Power Supply, and Switch)
[0045] As shown in FIG. 1, the first electrode 13a and the second
electrode 13b are electrically connected to the power supply 14
through an electric wiring and the switch 15.
[0046] The first electrode 13a and the second electrode 13b are
both disposed to be in contact with the heat storage material 12.
The distance between parts of the first electrode 13a and the
second electrode 13b which are in contact with the heat storage
material 12 is not particularly limited. An example of the distance
is not less than 1 millimeter and not more than 30 millimeters.
[0047] The first electrode 13a has silver, a silver alloy, or a
silver compound on the surface thereof. Needless to say, the silver
or the silver alloy is in contact with the heat storage material
12. An example of the silver alloy is a silver palladium alloy or a
silver copper alloy. An example of the silver compound is a silver
halide or a silver oxide. An example of the silver halide is silver
bromide.
[0048] The second electrode 13b does not have to have silver, a
silver alloy, or a silver compound on the surface thereof. Needless
to say, the second electrode 13b may also have silver, a silver
alloy or a silver compound on the surface thereof.
[0049] The shapes of the first electrode 13a and the second
electrode 13b are not limited. The shapes of the first electrode
13a and the second electrode 13b are, for example, plate-shaped or
linear.
[0050] In place of the direct-current power supply 14, an
alternate-current power supply may be used.
[0051] The heat storage device 10 according to the present
embodiment may comprise a plurality of heat storage tanks 11. Each
of the heat storage tanks 11 may comprise the first electrode 13a
and the second electrode 13b, both of which are in contact with the
heat storage material 12. The plurality of the heat storage tanks
11 may be electrically connected in parallel to the direct-current
power supply 14.
[0052] (How to Use Heat Storage Device 10)
[0053] First, the heat storage material 12 is cooled and brought
into the supercooled state. In this way, the latent heat is stored
in the sodium acetate trihydrate.
[0054] Next, a voltage is applied between the first electrode 13a
and the second electrode 13b to release the supercooled state of
the heat storage material 12. The release of the supercooled state
of the heat storage material 12 by voltage application crystallizes
the heat storage material 12. As a result, the heat storage
material 12 releases the heat. In other words, the latent heat is
taken out.
[0055] (Reuse of Heat Storage Device 10)
[0056] After the heat storage material 12 releases the heat, the
heat storage device is heated at a temperature of not less than 58
degrees Celsius and not more than 80 degrees Celsius for repeated
use. In this way, the sodium acetate trihydrate contained in the
heat storage material 12 is melted. In other words, the
crystallized sodium acetate trihydrate (i.e., the sodium acetate
trihydrate in the solid state) is melted due to the heating. The
heat storage material 12 must not be heated at a temperature of not
less than 90 degrees Celsius. In case where the heat storage
material 12 is heated at a temperature of not less than 90 degrees
Celsius, as demonstrated in the comparative examples 4-12, the
viability of the cluster is significantly lowered.
[0057] However, even if the heat storage material 12 is heated at a
temperature of not less than 90 degrees Celsius, the fine
solid-phase heat storage material 12 may be formed again in the
pores of the inorganic porous material by the cooling at the low
temperature of not more than minus 30 degrees Celsius or by the
addition of the seed crystal in the supercooled state.
EXAMPLES
[0058] The present invention will be described in more detail with
reference to the following examples.
Inventive Example 1
[0059] The inventive example 1 is composed of the inventive
examples 1A-1D.
Inventive Example 1A
[0060] (Preparation of Heat Storage Device 10)
[0061] Sodium acetate (2.2 grams), water (1.8 grams), and a zeolite
having an average pore diameter of 0.9 nanometers were added to the
heat storage tank 11. The heat storage tank 11 was a glass sample
bottle having a capacity of 9 milliliters. The zeolite was
purchased from Tosoh Corporation under the trade name "X-type
zeolite, F-9". The addition amount of the zeolite was 20% by mass
with regard to the total weight of the sodium acetate and the water
(i.e., 4.0 grams). In other words, the addition amount of the
zeolite was 0.8 grams. Thus, the heat storage material 12
containing the zeolite and containing the sodium acetate trihydrate
as the main component was stored in the heat storage tank 11.
[0062] Next, the first electrode 13a and the second electrode 13b
each composed of an electric wire formed of silver were immersed in
the heat storage material 12. Each of the first electrode 13a and
the second electrode 13b had a diameter of 1.5 millimeters. The
length of the portion where the first electrode 13a and the second
electrode 13b were in contact with the heat storage material 12 was
approximately 5 millimeters. The heat storage tank 11 was covered
with a lid. In this way, the heat storage device 10 according to
the inventive example 1 was provided.
[0063] (Evaluation of Heat Storage Device 10)
[0064] The liquid heat storage material 12 contained in the heat
storage tank 11 was allowed to leave at rest at a temperature of 70
degrees Celsius for two hours. The present inventors believe that
the heat storage material 12 entered the pores of the zeolite in
this period. Subsequently, the heat storage material 12 was cooled
to minus 30 degrees Celsius. In this way, the heat storage material
12 was crystallized. The present inventors believed that both the
heat storage material 12 in the pores and the heat storage material
12 outside the pores were changed from the liquid state to the
solid state.
[0065] Next, the heat storage material 12 contained in the heat
storage tank 11 was heated at a temperature of 70 degrees Celsius
for one hour. Due to the heating, the heat storage material 12 was
melted. Next, the heat storage material 12 was allowed to leave at
rest at a stationary temperature of 80 degrees Celsius for a
stationary time of 15 minutes. Furthermore, the heat storage
material 12 was cooled to room temperature (approximately 25
degrees Celsius). A voltage of two volts was applied for
approximately two minutes between the first electrode 13a and the
second electrode 13b, and then, the present inventors visually
observed whether or not the heat storage material 12 was
crystallized. The evaluation was repeated six times. Table 1 shows
the observation results. The numerators of the fractions included
in Table 1 are the number of times that the heat storage material
12 is crystallized. The denominators of the fractions included in
Table 1 are the number of times of the evaluation (i.e., six
times).
Inventive Examples 1B-1 D
[0066] In the inventive examples 1B-1D, the experiment similarly to
the inventive example 1A was conducted except that the stationary
time was 30 minutes, one hour, and two hours, respectively. The
experimental results are shown in Table 1.
Inventive Example 2
[0067] The experiment similarly to the inventive example 1 was
conducted except for the following matters (i) and (ii).
[0068] (i) In place of the zeolite, mesoporous silica (purchased
from Sigma-Aldrich under the trade name "MCM-41", average pore
diameter: 2.5-3.0 nanometers) was used, and
[0069] (ii) The addition amount of the mesoporous silica was 15% by
mass (i.e., 0.6 grams) with regard to the total weight of the
sodium acetate and the water (i.e., 4.0 grams).
Inventive Example 3
[0070] The experiment similarly to the inventive example 1 was
conducted except for the following matter (i).
[0071] (i) In place of the zeolite, activated carbon (purchased
from Calgon Carbon Japan Co., Ltd. under the trade name "activated
carbon made from coconut shell", average pore diameter: 1.0
nanometer-3.0 nanometers) was used.
Inventive Example 4
[0072] The experiment similarly to the inventive example 1 was
conducted except for the following matter (i).
[0073] (i) In place of the zeolite, silica gel (purchased from Fuji
Silysia Chemical Co., Ltd. under the trade name "MB100", average
pore diameter: 10 nanometers) was used.
Inventive Example 5
[0074] The experiment similarly to the inventive example 1 was
conducted except for the following matter (i).
[0075] (i) In place of the zeolite, silica gel (purchased from Fuji
Silysia Chemical Co., Ltd. under the trade name "MB300", average
pore diameter: 30 nanometers) was used.
Inventive Example 6
[0076] The experiment similarly to the inventive example 1 was
conducted except for the following matter (i).
[0077] (i) In place of the zeolite, silica gel (purchased from Fuji
Silysia Chemical Co., Ltd. under the trade name "MB500", average
pore diameter: 50 nanometers) was used.
Comparative Example 1
[0078] The experiment similarly to the inventive example 1 was
conducted except that the zeolite was not added to the heat storage
tank 11.
Comparative Example 2
[0079] The experiment similarly to the inventive example 1 was
conducted except for the following matter (i).
[0080] (i) In place of the zeolite, silica gel (purchased from Fuji
Silysia Chemical Co., Ltd. under the trade name "MB800", average
pore diameter: 80 nanometers) was used.
Comparative Example 3
[0081] The experiment similarly to the inventive example 1 was
conducted except for the following matter (i).
[0082] (i) In place of the zeolite, silica (purchased from Kanto
Chemical Co., Ltd.) was used. The silica was formed of amorphous
silicon dioxide having no pores.
[0083] (Comparative examples 4-12) The experiments similarly to the
inventive examples 1-6 and the comparative examples 1-3 were
conducted except that the stationary temperature was 90 degrees
Celsius. The results are shown in Table 2.
TABLE-US-00001 TABLE 1 Stationary temperature: 80 degrees Celsius
Numerators: times that the heat storage material 12 was
crystallized. Denominators: evaluation times (i.e., six times)
Average Inorganic Pore Stationary Time Porous Diameter 15 30 One
Two Material (nanometers) minutes minutes hour hours Inventive
Zeolite 0.9 6/6 6/6 6/6 4/6 Example 1 Inventive Meso- 2.5-3.0 6/6
6/6 6/6 4/6 Example 2 porous silica Inventive Activated 1.0-3.0 6/6
6/6 6/6 6/6 Example 3 carbon Inventive Silica gel 10 6/6 6/6 6/6
6/6 Example 4 Inventive Silica gel 30 6/6 6/6 6/6 6/6 Example 5
Inventive Silica gel 50 6/6 6/6 6/6 6/6 Example 6 Comparative None
-- 6/6 3/6 3/6 2/6 Example 1 Comparative Silica gel 80 6/6 3/6 3/6
2/6 Example 2 Comparative Silica -- 6/6 3/6 2/6 2/6 Example 3
TABLE-US-00002 TABLE 2 Stationary temperature: 90 degrees Celsius
Numerators: times that the heat storage material 12 was
crystallized. Denominators: evaluation times (i.e., six times)
Average Inorganic Pore stationary time Porous Diameter 15 30 One
Two Material (nanometers) minutes minutes hour hours Comparative
Zeolite 0.9 3/6 2/6 1/6 0/6 Example 4 Comparative Meso- 2.5-3.0 4/6
2/6 1/6 5/6 Example 5 porous silica Comparative Activated 1.0-3.0
4/6 4/6 3/6 2/6 Example 6 carbon Comparative Silica gel 10 4/6 4/6
3/6 2/6 Example 7 Comparative Silica gel 30 5/6 4/6 4/6 2/6 Example
8 Comparative Silica gel 50 4/6 3/6 3/6 2/6 Example 9 Comparative
None -- 2/6 0/6 0/6 0/6 Example 10 Comparative Silica gel 80 2/6
0/6 0/6 0/6 Example 11 Comparative Silica -- 2/6 0/6 0/6 0/6
Example 12
[0084] As is clear from Table 1 and Table 2, the stationary
temperature needs to be not more than 80 degrees Celsius.
Otherwise, the crystallization of the heat storage material 12
often fails. As is clear from Table 1, the average pore diameter
needs to be not more than 50 nanometers. Otherwise, the
crystallization of the heat storage material 12 often fails.
[0085] As is clear from Table 1, from the viewpoint of the
inevitable crystallization of the heat storage material 12, it is
desirable that the inorganic porous material is silica gel or
activated carbon.
[0086] As demonstrated in the above examples, by adding the
inorganic porous material having the average pore diameter of not
more than 50 nanometers to the heat storage material 12, even after
the heat storage material 12 is held at the high temperature of not
less than the melting point thereof (i.e., not less than 58 degrees
Celsius) and not more than 80 degrees Celsius, the latent heat is
allowed to be taken out by voltage application.
INDUSTRIAL APPLICABILITY
[0087] In the heat storage device according to the present
invention, even after the heat storage material 12 is held at a
high temperature in the liquid state, the latent heat can be taken
out by voltage application.
[0088] As an example, the heat storage device according to the
present invention is mounted in a vehicle comprising an engine
configured to drive wheels. The heat released from the heat storage
material 12 is used to warm up an internal combustion engine such
as an engine provided in a vehicle. The heat storage device
according to the present invention is also mounted in a boiler, an
air conditioner, or a water heater.
REFERENTIAL SIGNS LIST
[0089] 10 Heat storage device [0090] 11 Heat storage tank [0091] 12
Heat storage material [0092] 13 Electrode [0093] 14 Direct-current
power supply [0094] 15 Switch [0095] 20 Surface of activated carbon
[0096] 21 Macropore [0097] 22 Micro mesopore
* * * * *